Conventional floor finishes are periodically applied to a variety of flooring substrates such as vinyl composition tile, stone, terrazzo, linoleum, wood, etc., to improve use life and to enhance the visual appearance of the floor. Acrylic floor finish can be applied with a mop and removed with chemical stripper. However, acrylic finish is not alcohol-resistant. Alcohol-resistance has become increasingly important with the increasing use of alcohol-based hand sanitizers, which have come into extensive use in hospitals, airports, homes, and elsewhere. If an alcohol-based hand sanitizer spills onto a floor having an acrylic finish, after a short period of time the hand sanitizer visually and chemically degrades the finish,
Although conventional polyurethane floor finish is alcohol-resistant and can be applied with a mop, it cannot be readily removed with chemical floor stripper. Rather, removal of conventional polyurethane floor finish is carried out using an abrasive to grind the finish off the flooring substrate.
Recently a chemically-strippable polyurethane floor finish system has been commercialized. This polyurethane floor finish system has a relatively high degree of alcohol-resistance, while also being chemically-strippable. This floor finish system is a two-component system in which a polyol component is mixed with a polyisocyanate component shortly before the mixture is applied to a substrate, such as a flooring substrate. The mixture has a limited pot life as the polyol reacts with the polyisocyanate to form a polyurethane network, i.e., eventually becoming so viscous that if not used by that point, it loses utility because it is too viscous to be applied to a substrate and form a film therewith. The two-component system has a pot life of from 3-10 hours during which the coating material has suitable viscosity for its intended use in floor application procedures as the polyol and polyisocyanate react to form the crosslinked polyurethane.
The commercially-available stripper for the removal of the commercial coating, although VOC-compliant (i.e., volatile organic compound-compliant) contains potassium hydroxide. The label on the stripper states that it not recommended for use on linoleum, rubber, marble, or wood floors. The label further states that the stripper is recommended for use on vinyl composition tile, vinyl asbestos tile, ceramic tile, terrazzo, and concrete floors. The recommendation against the use of the stripper on linoleum, rubber, marble, and wood may be due to the presence of the potassium hydroxide, which may cause damage to linoleum, rubber, marble, and/or wood flooring substrates.
It would be desirable to provide an alcohol-resistant polyurethane floor coating which is chemically-strippable and is easier to chemically strip with a stripper free of a caustic component. It would be desirable if the coating is chemically strippable with a wide variety of chemical strippers, including strippers compatible with stripping the coating composition from linoleum, rubber, marble, and/or wood flooring substrates, as well as strippers incompatible stripping the coating composition from linoleum, rubber, marble, and/or wood flooring substrates. It would also be desirable to provide a coating system that has a pot life long enough to allow excess composition to be stored for 2 to 10 days or more without exceeding the pot life.